Joint for folding rules.



C. BODMER.

JOINT FOR FOLDING RULES.

APPLICATION FILED 1350.7, 1908.

\ 28,174. Patented July13, 1909.

I IEI .UMHMMIIEWW as well as durabilit UNITED STATES PATENT oFEIoE.

CHRISTIAN BODMER, OF NEW BRITAIN, CONNECTICUT, hSSIGNOR TO THE STANLEY RULE & LEVEL COMPANY, OF NEW BRITAIN, CONNECTICUT, A CORPORATION OF CONNECTICUT.

JOINT FOR FOLDING RULES.

Specification of Letters Patent.

Patented July 13, 1909.

Application filed December 7, 1908. Serial No. 466,227.

To all whom it may concern:

Be it known that I, CHRISTIAN BODMER, a citizen of the United States, residing at New Britain, county of Hartford, State of Connecticut, have invented certain new and useful Improvements in Joints for Folding Rules, of which the following is a full, clear, and exact description.

My invention relates to improvements in rule joints for folding rules of the type sometimes termed snake rules, in which the several sections are connected b a pivot passing through the flat surfaces 0 the over lapping ends of said several sections.

One ob'ect of the invention isto provide a means w ereby the original length of the rule determined b the uniting of the several sections shall, w en opened up, be etfec-v tually maintained. In the ordinary rule of this character, any im erfection or wear of the pivotal joints (w ere there are from three to,.fifteen joints) destroys the accuracy of the measuringle'ngth of the instrument. This is by reason of the fact that, when opened up, said sections slide toward, or away, from each other to such'an extent as to abnormally shorten or lengthen the rule and prevent perfectly accurate measurement. My improvement overcomes this defect, and also provides a construction whichhas the maximum perfection of original construction and resistance to wear.

In the drawings igure 1 is an edge ele'va tion of a rule constructed to embody m invention in its preferred form and folde up. In this figure the central part of the folded rule is broken away slightly. Fig. 2 is a rela+ tively enlarged sectional view of one of the joints, said section being taken coincident with the axis of the pivotal connection. Fig. 3 is a plan view-of one part of the metallic portion of the joint. Fig. 4 is a section on the-line 4-4 Flg. 3. Fig. 5 is a view similar to Fig. 2 and illustrating a modification. Fig. 6 is a plan view of one of the parts of the metallic portion of the modified joint shown in Fig. 5, illustrating a form on which the end enlargements are of the same depth as the intermediate depressions.

In all the figures, 1-11 represent. the several sections of the rule, upon which the proper graduations (not shown) are placed in the usual manner. These several sections overlap at their ends, and the overlapped portions are connected by suitable pivotal means, whereby said sections may be the spring in place;

straightened out into line for the purpose of measurement. The pivot proper is indicated'at 2.

3-3 are so-called body plates, arranged in sets of two each for each joint. Both body plates of a single set are. of corresponding shape and are struck up along thelongitudinal middle line to provide locking recesses on one part and cooperatin locking projections on the other part. In t 1e preferred form of these parts (shown in Figs. 1 to 4), 4 is the central longitudinal recessed portion in each body plate, while 5-5 are enl'ar ed and relatively deepened recesses at eac end. The projectin portion of one plate is arranged to nest and interlock in the recessed portion of the other plate, whenthe plates are in line. The walls bounding these projected and recessed portions 4-5 are beveled, so that the two body plates 33 may beswung around, one upon the other, when sufficient force is applied. i

6 is a spring which operates to hold the two body plates 3'3 in yielding engagement. 2 is a pivot in, which has a head 2 standing above sai plates 3.-3, the. shank being passed through said plates and spring 6, and being'riveted or rrplset'slightly to hold en the onset portions of said plates nest one within the other, said body ally against in ependent rotary movement in any direction, each' of the enlarged interplates be 'held friction- Y p e, as side clamping flanges 77 and the struck-up tangs 88.

It is not necessary that the enlarged interlocking ends 5-5 of the recess be of any definite-shape, so long as such shape is suitable to prevent or guard against endwise movement in both directions, that being the function of each of said enlargements. In the preferred form, both endsof each recess 4 are provided with an interlocking enlargement 5, although it is possible to dispense with one of such enlargements in one plate, to wit, in the plate which projects into the other.

In Figs. 5 and 6 I have illustrated modified enlargements 5*5 at each end of the recessed portion 4, which enlargements are of angular outline instead of being of curved outline, as shown in Fig. 3, and are also of the same depth as said-recess 4. Otherwise, the structure of Figs. 5 and 6 is substantially similar to what has already been described.

Since the body plates 33 cannot shift longitudinally one upon the other, even though the ivot 2 becomes worn or is loose in the first instance, it follows that the rule sections 11 cannot shift longitudinally one upon the other where they overlap, and hence accurate measurement is guaranteed at all times. i 4

The adjacent faces of the rule sections 1-1, where they overlap, are of course recessed, for the pur ose of providing space for the reception of t e metallic portion of the joint. p

In practice it is preferred to have the body plates provided with the recessed portion arrange which crosses the center, as this affords greater frictional resistance, stifiens each plate and rovides a spring receiving pocket that afl'or s greater compactness than would be the case if the recesses were only at oppo site ends of each plate.

What I claim is:

1. In a rule joint, the combination of two body plates, one of the same having formed across its ivot center and along the longitudinal mid le line a recess, said recess having a laterally enlarged locking recess at each end, the other plate having a corresponding projection enlarged at one end and arranged to frictionally interlock in a recess of the first mentioned plate, a pivot, and a spring cooperating wit said p ates to cause the same to bear frictionally against each other. -2. In a rule joint, two metallic body plates, a pivot dpassing through the same, a sprin to hold said plates into frictiona contact, one of said lates having a recess extending longitudina y thereof along the middle line and across the pivot center, both ends first mentioned i tionally engage t warm of said recess being enlarged laterally, a projection on the other plate conforming substantially to the shape of the recess in the 1plate and arranged to fricerein when said body plates are in alinement.

3. In a rule joint, two metallic body plates,

a pivot therefor, each body plate having a struck down recess extending along the longitudinal middle line and across the central pivot portion, the projected side of one plate entering the recess of the other plate, a spring standing in one recess and held by said pivot, the ends of each recess in each plate being correspondingly widened or enlarged to prevent longitudinal sliding movement of one or the other when the plates are in line.

4. In a rule joint, two metallic bod plates, a pivot therefor, one of said body p ates being recessed on its longitudinal m1ddle line and across its pivot center, a projection on the other plate arranged to fit in the recess of the first mentioned plate, a'spring to yieldingly hold said plates together, eachend of the recess being deepened and each end of the projection being' correspondingly extended to afford an interlocking connection between said plates when the same are in line and nested to prevent the longitudinal shifting of one plate on the other.

5. In rule oints, two metallic body plates,

a pivot therefor, one of said body plates being recessed along the middle lineand ex tending across the-center, a locking projection formed in the other plataby recessing one side, a s ring standing in said recess last -me1itioned, oth ends of both the recess and the locking projection being relatively enlarged and deepened to afford a second inter locking connection between said plates when the same are in line and nested. 

